<?php

// This file is part of BOINC.
// http://boinc.berkeley.edu
// Copyright (C) 2008 University of California
//
// BOINC is free software; you can redistribute it and/or modify it
// under the terms of the GNU Lesser General Public License
// as published by the Free Software Foundation,
// either version 3 of the License, or (at your option) any later version.
//
// BOINC is distributed in the hope that it will be useful,
// but WITHOUT ANY WARRANTY; without even the implied warranty of
// MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.
// See the GNU Lesser General Public License for more details.
//
// You should have received a copy of the GNU Lesser General Public License
// along with BOINC. If not, see <http://www.gnu.org/licenses/>. 
//
// This file was modified by contributors of "BOINC Web Tweak" project.



////// stuff related to snapshots
//
// There are 2 kinds of snapshots: "compare" and "map".
//
// A "compare snapshot" is a condensed representation of the results
// for a particular select/xset pair.
// Namely, it's an array whose elements contain
//  bolt_user: the user
//  xset_result: the user's first completion of the xset
//  select_finished: the user's last completion of the select before this
//
// A "map snapshot" is:
// - an assoc array "views" mapping unit name to a list of views
// - an assoc array "results" mapping unit name to a list of results
// - an assoc array "xset_results" mapping unit name to a list of xset results
// - an assoc array "questions" mapping unit name to a list of questions
// - an assoc array "users" mapping user ID to user record
//


function compare_snapshot_filename($course_id, $select_name, $xset_name) {
	@mkdir("../bolt_snap");
	$x = urlencode($course_id."_".$select_name."_".$xset_name);
	return "../bolt_snap/compare_snapshot_$x";
}

function write_compare_snapshot($course_id, $select_name, $xset_name, $dur) {
	$now = time();
	$start = $now - $dur*86400;
	$xrs = BoltXsetResult::enum(
		"course_id=$course_id and name='$xset_name' and create_time >= $start"
	);
	$sfs = BoltSelectFinished::enum(
		"course_id=$course_id and name='$select_name' and end_time >= $start"
	);

	// make an array $a, keyed by user ID, of earliest xset result
	//
	$a = array();
	foreach ($xrs as $xr) {
		$uid = $xr->user_id;
		if (!array_key_exists($uid, $a) || $xr->create_time < $a[$uid]->xr->create_time) {
			$x = null;
			$x->xr = $xr;
			$a[$uid] = $x;
		}
	}

	// now scan select finishes, and for each user find last one before xset
	//
	foreach ($sfs as $sf) {
		$uid = $sf->user_id;
		if (!array_key_exists($uid, $a)) {
			echo "no xset result";
			continue;
		}
		$x = $a[$uid];
		$xr = $x->xr;
		if ($sf->end_time > $xr->create_time) {
			//echo "select finish is too late";
			continue;
		}
		if (!isset($x->sf) || $sf->end_time > $x->sf->end_time) {
			$x->sf = $sf;
			$a[$uid] = $x;
		}
	}

	// cull array elements for which we didn't find a select finish.
	// Look up user records for other elements.
	//
	foreach ($a as $uid=>$x) {
		if (!isset($x->sf)) {
			unset($a[$uid]);
		} else {
			$user = BoincUser::lookup_id($uid);
			BoltUser::lookup($user);
			$x->user = $user;
			$a[$uid] = $x;
		}
	}

	$filename = compare_snapshot_filename($course_id, $select_name, $xset_name);
	$f = fopen($filename, "w");

	$s = null;
	$s->recs = $a;
	$s->dur = $dur;
	$s->time = $now;
	fwrite($f, serialize($s));
	fclose($f);
	return $s;
}

function read_compare_snapshot($course_id, $select_name, $xset_name) {
	$filename = compare_snapshot_filename($course_id, $select_name, $xset_name);
	$f = @fopen($filename, "r");
	if (!$f) return null;
	$x = fread($f, filesize($filename));
	fclose($f);
	return unserialize($x);
}


function map_snapshot_filename($course_id) {
	return "../bolt_snap/map_snapshot_".$course_id;
}

function write_map_snapshot($course_id, $dur) {
	$now = time();
	$start = $now - $dur*86400;

	$views = array();
	$results = array();
	$xset_results = array();
	$users = array();
	$questions = array();

	$vs = BoltView::enum("course_id=$course_id and start_time>$start");
	foreach ($vs as $v) {
		if (array_key_exists($v->item_name, $views)) {
			$x = $views[$v->item_name];
			$x[] = $v;
			$views[$v->item_name] = $x;
		} else {
			$views[$v->item_name] = array($v);
		}
		if (!array_key_exists($v->user_id, $users)) {
			$user = BoincUser::lookup_id($v->user_id);
			BoltUser::lookup($user);
			$users[$v->user_id] = $user;
		}
	}

	$rs = BoltResult::enum("course_id=$course_id and create_time>$start");
	foreach ($rs as $r) {
		if (array_key_exists($r->item_name, $results)) {
			$x = $results[$r->item_name];
			$x[] = $r;
			$results[$r->item_name] = $x;
		} else {
			$results[$r->item_name] = array($r);
		}
		if (!array_key_exists($r->user_id, $users)) {
			$user = BoincUser::lookup_id($r->user_id);
			BoltUser::lookup($user);
			$users[$r->user_id] = $user;
		}
	}

	$xrs = BoltXsetResult::enum("course_id=$course_id and create_time>$start");
	foreach ($xrs as $xr) {
		if (array_key_exists($xr->name, $xset_results)) {
			$x = $xset_results[$xr->name];
			$x[] = $xr;
			$xset_results[$xr->name] = $x;
		} else {
			$xset_results[$xr->name] = array($xr);
		}
		if (!array_key_exists($xr->user_id, $users)) {
			$user = BoincUser::lookup_id($xr->user_id);
			BoltUser::lookup($user);
			$users[$xr->user_id] = $user;
		}
	}
	$qs = BoltQuestion::enum("course_id=$course_id and create_time>$start");
	foreach ($qs as $q) {
		if (array_key_exists($q->name, $questions)) {
			$x = $questions[$q->name];
			$x[] = $q;
			$questions[$q->name] = $x;
		} else {
			$questions[$q->name] = array($q);
		}
		if (!array_key_exists($q->user_id, $users)) {
			$user = BoincUser::lookup_id($q->user_id);
			BoltUser::lookup($user);
			$users[$q->user_id] = $user;
		}
	}

	$y = null;
	$y->views = $views;
	$y->results = $results;
	$y->xset_results = $xset_results;
	$y->users = $users;
	$y->questions = $questions;
	$y->dur = $dur;
	$y->time = $now;

	$filename = map_snapshot_filename($course_id);
	$f = fopen($filename, "w");
	fwrite($f, serialize($y));
	fclose($f);

	return $y;
}

function read_map_snapshot($course_id) {
	$filename = map_snapshot_filename($course_id);
	$f = @fopen($filename, "r");
	if (!$f) return null;
	$x = fread($f, filesize($filename));
	fclose($f);
	return unserialize($x);
}

?>
